On macrophage response to primary Mycobacterium tuberculosis in humans

Tuberculosis stands as the leading cause of death worldwide, driven by infection from a single bacterial agent, and has been recognized as a global public health concern by the World Health Organization. Recent studies highlight that the innate immune response has a central role in controlling the initial spread of Mycobacterium tuberculosis (Mtb) within the host, and triggers adaptive immune response. We developed and analyzed a model examining the interactions among macrophages, innate cells, and Mtb to determine whether the infection is controlled by the innate immune response or whether a specific adaptive response is triggered. Findings suggest that if an individual infected by Mtb has an adequate immunological state to prevent bacteria from infecting the macrophage population (that is, if the external bacteria engulfed by macrophages are eliminated by them, or if their capacity to replicate inside them is limited), then the innate immune response will effectively control the primary infection.